he used a weapon to walked in. stephanopoulos: 'he blasted right through it?' with several rounds.a number of rounds. he discharged to make an opening and then went through it. went to the first classroom, as you know, went to the second classroom. we surmise that it was during the second classroom episode that he heard responders coming and apparently at that decided to take his own life." >>reporter: officials say adam lanza killed himself with a single bullet to the head, and the bullet was recovered in a classroom wall. authorities say they found multiple 30-round magazines and hundreds of bullets at the school. that suggests that the gunman was planning an even more gruesome massacre, but was stopped short. officials say before heading to the school, lanza fatally shot his mother, nancy, four times in the head at their home. the official says nancy lanza was found in her bed, wearing pajamas. it's not clear what time she was killed. the massacre at sandy hood elementary has brought the hot topic of gun control back into the crosshairs of politicians. today